Mine prop



H. THINES July 20, 1948.

MI NE PROP 2 Sheets-Shet 1 Filed Sept. 7, 1945 H. THINES- July 20, 1948.

MINE PROP 2 Sheets-Sheet 2 Filed Sept. 7, 1945 p M y\ an F. 8 \\4 LM 5 0 o u w the rotation mm 3 are limited by amp-.9,

which in Fig. 2 is formed by an upstanding edge of the outer column 2. When the shoe comes 1 to rest on said stop, the maximum locking efiect is obtained. If this is not sufiicient to balance the force Q, the inner colunm I will continue its downward movement.

obvious that they may be of the socket type. The fixed shoe is welded to the upper end of column 2. The operation of this device is identical with that described with reference to Fig. 2.

Fig. 11 shows a modification of the arrangement just described, wherein it is the locking arm 3 that comprises two elements embracing column I and resting on b o1t;8. In this case also the operation is the same, the locking arm 3 now swinging about the bolt 8.

Other modification may of course be made within the scope of the invention. Thus, instead of resting in a fixed support, the bolt 8 may be interposed between the locking arm 3 and the Instead of being unmovable asshown in Fig.

permitting the, toggle arms .to'swing and move the centres O 0'} towards each other about 0 and instantaneously releasing the lock on column l.

The initial position of the bolt 8 in its longitudinal direction maybe adjusted, thereby permitting of adjusting at will the position of centre 0 and consequently the size of the angle 0' O O" and of the vertical thrust P3 acting on the bolt.

Thi makes it possible to reduce if desired the force to be applied to the bolt 8 in order'to release thelock.

Instead of one set of, togglear msthere maybe two-or more sets. In the-example of Fig. 5 two sets of toggle arms. 3,.4 arranged in planes at right angles to each other, act on two adjacent sides ofthe inner column I, In the example of Fig. 6, the sets of togglearms acting on adjacent sides of column I are parallel toone another, the shoes 5 being of triangular cross-section.

In Fig. 9 are shown two sets of toggle arms in superposed relation, acting on the same f ric-- tion shoe 5. In this embodiment the'counterarms 4 rest one on the other and a single. bolt 8 is adapted to release the lock. v p I ,I have also shown in this; example a fixed shoe 6 separate from the collar 1 and bearing thereon through the medium of a wedge. Ill adapted to permit of a supplemental adjustment of the angle formed by theaxesofthearmstand 4. p

Figs. 7. and 8 illustrate the invention as applied to props respectively of hexagonal and circular cross-section. In the latter case, the form of the shoe 5 is adapted to surround a sufficient surface of the column I to ensure an efficientlock. The arrangement of shoe 6 withan adjustable wedge lll isalso shown in these figures. I Instead of being arranged onone sideonly of the column I, the set of toggle arms may embrace. the-columnsso that the arms themselves form the locking collar. Two examples of such an arrangement are shown in Figs. 10 and; '11.;

Int he constructional forma shown .in Figs 10 and 12, the-counter arm 4 is formed of two ele ments arranged oneither side-of the column I and resting in the bolt-8 which in turn rests in a side shoulder l2 on column 2.1 The-pivotal engagement between arms 3 and l on the one hand,

and-that betweenarm. 4V and shoe .6 on the-other hand, are shown to comprise a pivot, but it is counter-arm 4 which are then provided, to that endywith projections l3, [4 having notches to engage the bolt 8 as shown in Fig. 13. The movement of bolt 8, as in the preceding instances, results in causing the angle 0' O O" to vary according to the principle applied by this invention. J V

I claim: I

1. Ina metal mine 'prop, the combination of an outer column, an inner column slidable in said outer column, means for locking said inner column in said outer column, said locking means comprising a art in frictional engagement with said inner column and movable therewith, a stationary parton said "outer column, and a threejoint toggle between said parts comprising a looking arm'and a [counter-arm, said armshaving apivotal engagement with each other, one of said arms having a pivotal engagement with one of said parts, the other of said arms having a pivotal engagement withthe other of said parts, a projection on each of said toggle arms, said projections facing each other, and a wedge-shaped bolt engaged between said projections.

2. In a metal mine prop, the combination of an outer column, an inner column slidable in said outer column, a part in frictional engagement with said inner column and movable therewith, a part'rigidly fixed to said outer column, a threejointtoggle between said parts comprising a locking arm and a counter-arm, a wedge-shaped bolt under said toggle arms, one of said toggle arms resting on said bolt;

3..In a metal mine prop, the combination of an outer column, an'inner column slidable in said outer. column,fa shoe in frictional engagement with said inner, column and movable therewith, a shoe rigidly fixed to said outer column, .a

three-joint toggle comprising a, locking arm and a" counter-arm interposed between said shoes, said arms'having each a pivotal engagement with one of said shoes and a pivotal engagement with one another, a wedge-shaped bolt carried by said outer column, said toggle-arms bearing on said bolt. I

4. In a metal mine prop, the combination of an outer column, 'an inner column slidable in said outer'column, a shoe in frictional engagement With said inner column and movable therewith,

ashoe rigidly fixed to said outer column, a toggle for automatically locking said movable shoe with respect to said fixed shoe as said movable shoe movesdownward-ly with said inner column, and aremovable bolt under saidtoggle for collapsing same.

5.'In a metal mine. prop, the combination of anouter, column, an inner column slidable in said outercolumn, a shoein frictional engagement with saidinner column and movable therewith,

said movable shoe and said fixed shoe, and a stop on said outer column for limiting the downward movement of said movable shoe.

6. In a metal mine prop according to claim 2, one of said toggle arms being yoke-shaped and embracing said inner column.

7. In a metal mine prop according to claim 2, one of said toggle arms being yoke-shaped and embracing said inner column, said yoke-shaped arm resting on said wedge-shaped bolt, a bracket on said outer shaft for accommodating said bolt.

8. In a metal mine prop according to claim 2, means for adjusting the position of said toggle arms with respect to each other independently of said bolt.

9. In a metal mine prop, the combination of an outer column, a collar piece rigidly secured to the top of said column, an inner column slidable in said outer column and collar piece, and means for clamping said inner column against said collar piece comprising a shoe frictionally en- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,575,818 Carrier Mar. 9, 1926 20 2,297,469 Groetschel Sept. 29, 1942 

